C语言中用random函数需要什么头文件

[stephanie_sume]

在c语言中想用random（），需要什么头文件？

ps：加了"stdlib.h"
还是不对啊？？？？

[mstlq]

#include <stdlib.h>
void srand( unsigned seed );
int rand( void );


例子

#include <stdlib.h>
#include <time.h>

srand( time(NULL) );
   for( i = 0; i < 10; i++ )
     printf( "Random number #%d: %d\n", i, rand() );    

[mian123yang]

顶下！

[老吴笔记]

stdlib.h

[ikano]

#include <stdlib.h>
int rand(void);

例 n = rand( );范围是（0到32767）

[jianglutian]

Generates a pseudorandom number. A more secure version of this function is available, see rand_s.

 
int rand( void );
 

Return Value
rand returns a pseudorandom number, as described above. There is no error return.

Remarks
The rand function returns a pseudorandom integer in the range 0 to RAND_MAX (32767). Use the srand function to seed the pseudorandom-number generator before calling rand.

Requirements
Routine
 Required header
 
rand
 <stdlib.h>
 

For additional compatibility information, see Compatibility in the Introduction.

Example
  Copy Code 
// crt_rand.c
// This program seeds the random-number generator
// with the time, then exercises the rand function.
//

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

void SimpleRandDemo( int n )
{
   // Print n random numbers.
   int i;
   for( i = 0; i < n; i++ )
      printf( "  %6d\n", rand() );
}

void RangedRandDemo( int range_min, int range_max, int n )
{
   // Generate random numbers in the half-closed interval
   // [range_min, range_max). In other words,
   // range_min <= random number < range_max
   int i;
   for ( i = 0; i < n; i++ )
   {
      int u = (double)rand() / (RAND_MAX + 1) * (range_max - range_min)
            + range_min;
      printf( "  %6d\n", u);
   }
}

int main( void )
{
   // Seed the random-number generator with the current time so that
   // the numbers will be different every time we run.
   srand( (unsigned)time( NULL ) );

   SimpleRandDemo( 10 );
   printf("\n");
   RangedRandDemo( -100, 100, 10 );
}
 
  Copy Code 
   22036
   18330
   11651
   27464
   18093
    3284
   11785
   14686
   11447
   11285

      74
      48
      27
      65
      96
      64
      -5
     -42
     -55
      66
 

[xmt_0114]

用rand()函数，不是random()